1007.cpp

这是在acm上所做的1005-1007

#include <stdio.h>
#include <string.h>

#define	  N   1500

void  reserve(char x[],int lx){
	int i;
	char temp;
	for(i=0;i<=lx/2;i++){
		temp=x[i];
		x[i]=x[lx-i];
		x[lx-i]=temp;
	}
}
void mul(char a[],char b[],int result[]){

	int i,j,la,lb,lr;
	int temp;
	la=strlen(a)-1;
	lb=strlen(b)-1;
	reserve(a,la);
	reserve(b,lb);

	for(i=0;i<=la;i++)
		for(j=0;j<=lb;j++){
			result[i+j]+=(a[i]-'0')*(b[j]-'0');
			result[i+j+1]+=result[i+j]/10;
			result[i+j]%=10;
		}

	lr=la+lb+1;
	while(result[lr]==0)
		      lr--;
    if(lr<0)
		lr=0;
	for(i=0;i<=lr/2;i++){
		temp=result[i];
		result[i]=result[lr-i];
		result[lr-i]=temp;
	}

	for(i=0;i<=lr;i++)
		printf("%d",result[i]);
	putchar('\n');

}

int main(){

	char a[N]={0},b[N]={0};
	int  result[2*N]={0};

	scanf("%s%s",a,b);
   
	mul(a,b,result);

	return 0;


}